body {
    width: 100%;
    min-width: 320px;
    max-width: 640px;
    margin: 0 auto;
    background-color: #ccc;
}
ul {
    margin: 0;
    padding: 0;
}
li {
    list-style: none;
}
.app {
    height: 45px;
}
.app ul li {
    float: left;
    height: 45px;
    background-color: #333;
    line-height: 45px;
    text-align: center;
}
.app ul li:nth-child(1) {
    width: 8%;
}
.app ul li:nth-child(1) img {
    width: 16px;
}
.app ul li:nth-child(2) {
    width: 10%;
}
.app ul li:nth-child(2) img {
    width: 35px;
    vertical-align: middle;
}
.app ul li:nth-child(3) {
    width: 57%;
    color: #fff;
}
.app ul li:nth-child(4) {
    width: 25%;
    background-color: #f63515;
    color: #fff;
}
/* 搜索 */
.search-wrap {
    position: relative;
    /* 解决塌陷 */
    overflow: hidden;
    height: 44px;
}
.search-btn {
    position: absolute;
    top: 0;
    left: 0;
    background-color: #333;
    width: 40px;
    height: 44px;
}
.search-login {
    position: absolute;
    right: 0;
    top: 0;
    background-color: #333;
    width: 40px;
    height: 44px;
}
.search {
    height: 30px;
    background-color: #fff;
    margin: 7px 50px;
    border-radius: 15px;
}